1. Field of the Invention
The present invention relates to a yarn unwinding assisting device and method in an automatic winder which pieces a yarn of a plurality of yarn feed bobbins produced by a ring spinning machine, for example, and winds a yarn on a cone- or cheese-like winding package while removing defective portions of a slub or the like, and particularly to a yarn unwinding assisting device which enables the implementation of high speed winding.
2. Prior Art
The automatic winder is composed of a plurality of spindles of winding units, and the arrangement of a device for one of the spindles will be described below.
In FIG. 11, a winding unit 1 is fixed in position by a support tube 2 and a duct 3, and a yarn Y drawn from a yarn feed bobbin 4 positioned at a predetermined position of the unit and supplied passes through a balloon breaker 6, a disk- or gate-type tensor 7 for applying a predetermined tension, a slub catcher 8 for detecting a defective portion of the yarn, and the like, after which the yarn is wound on a winding package 14 which is rotated by a traverse drum 13. Reference numeral 15 denotes a splicing device; 16 a suction mouth for guiding an upper yarn on the package side to the splicing device 15; and 17 a relay pipe for guiding a lower yarn on the yarn feed bobbin side. The winding units are each provided with the aforementioned members. A plurality of these winding units 1 are juxtaposed to constitute an automatic winder. The yarn feed bobbin 4 is inserted into an independent tray, 18, under which state, the bobbin 4 is supplied to a winding position A of the winding unit 1 through a supply conveyor 11 and a rotary disk 19. A wound empty bobbin 4' is discharged to a discharge conveyor 12, and a new yarn feed bobbin 4 is instead supplied. A yarn end Y1 is inserted into a hollow portion of a head of the yarn feed bobbin 4 so that the yarn Y of the yarn feed bobbin 4 located at the winding position A is blown up and attracted into the relay pipe 17.
In the winding unit 1, when the slub catcher 8 detects a defective portion of the yarn, an accessory cutter is actuated to cut the yarn. The splicing is carried out when a yarn running signal of the slub catcher 8 is turned OFF. The splicing operation will be described with reference to FIG. 12. In FIG. 12, the suction mouth 16 turns in a direction of 1 so that a suction port 16a is positioned between the traverse drum 13 and the winding package 14 to such a yarn end of winding package 14. When the suction mouth 16 assumes a predetermined position, the traverse drum 13 or the winding package 14 is reversed by a reversible roller or the reversal of a drive motor within a frame 5 to unwind the yarn, and the yarn end is sucked into the suction mouth 16. Substantially simultaneous with the actuation of the suction mouth 16, the relay pipe 17 turns in a direction of 2 to assume a position below the tensor 7. Then, the tensor 7 is opened so that the yarn end unwound from the tensor 7 is sucked into the relay pipe 17. In the change of a bobbin, the yarn blown up from the yarn feed bobbin is sucked into the relay pipe 17. Then, when the suction mouth 16 and the relay pipe 17 having sucked the yarn end on the winding package side and the yarn feed bobbin side are reversely turned and returned to the illustrated position, the yarn enters the splicing device 15 for splicing.
Also when a yarn feed bobbin becomes empty or when a yarn breakage occurs, the aforementioned splicing is carried out with a yarn running signal OFF of the slub catcher 8 as a start point. However, in the event the yarn feed bobbin becomes empty, the splicing operation fails because the lower yarn is not present. Therefore, a yarn feeler 9 is provided at the lower side of the tensor 7 in order to confirm the presence or absence of the lower yarn so that when the yarn feeler 9 does not detect the lower yarn, the bobbin changing is carried out at the same time of the splicing operation. This bobbin changing is carried out by the cooperation between the rotation of the rotary disk 19 (see FIG. 11) and the turning operation of an injection lever (not shown) so that the empty bobbin 4' is discharged, and a new yarn feed bobbin 4 is supplied. Such a lower yarn detecting yarn feeler 9 comprises a mechanical or an optical sensor.
In the aforementioned winding unit 1, a cone- or cheese-like winding package is formed while removing a defective portion such as a slub from the yarn unwound from the yarn feed bobbin and while carrying out the splicing every yarn feed bobbin, and therefore, the productivity greatly depends upon the winding speed. However, in the conventional automatic winder, the practical winding speed is about 1000 m/min. The winding speed has been restricted due to the combination of phenomena (a) to (c) mentioned below. (a) As the winding speed increases, the unwinding tension also increases. Particularly, when the remaining yarn amount on a bobbin is 1/3, referred to herein as a "skinny bobbin", unwinding tension abruptly increases. When this increase becomes large in degree, a yarn breakage caused by the tension occurs. (b) As the winding speed increases, sloughing increases. This sloughing is the state where the yarn is not stably unwound from a chase portion 4a of the yarn feed bobbin 4 but the yarn is unwound at a time with some coils are entangled as in an escape through a ring, which comprises a cause of a yarn breakage. (c) As the winding speed increases, fuzz increases.
It has been known in terms of experience that these phenomena (a) to (c) depended on the state of yarn unwinding from the yarn feed bobbin. Therefore, as shown in FIG. 11, a balloon of a yarn unwound from the yarn feed bobbin 4 is restricted by the balloon breaker 6 in the form of a square cone tube to maintain it to be a moderate configuration to prevent the balloon from being excessively widened. However, since the balloon breaker 6 is positioned from the lower side of the guide plate to the upper side of the yarn feed bobbin 4 and secured to the frame 5, as the unwinding of the yarn feed bobbin 4 proceeds, the distance from the chase portion 4a of the yarn feed bobbin 4 to the lower end of the balloon breaker 6 gradually becomes lengthened, whereby the function of the balloon breaker 6 likely becomes worsened. In view of this, there is proposed one in which the balloon breaker 6 is formed into a cylindrical shape which is gradually moved down following the release of the yarn feed bobbin.
However, the shape of the conventional balloon breaker has not been so adequate as to compensate the phenomena (a) to (c). As a result, there is a problem in that a practical winding speed of about 1000 m/min. has not been increased.